The Global Trachoma Mapping Project: A Catalyst for Progress Against Neglected Tropical Diseases

Purpose: In suspected trachoma-endemic areas of Yemen, we sought to determine the prevalence of the sign trachomatous inflammation-follicular (TF) in children aged 1-9 years, and the potential individual and household risk factors for TF in that age group. We also sought to determine the prevalence of trichiasis in adults aged ≥15 years. Methods: We conducted a cluster-sampled survey in each of 42 evaluation units (EUs) comprising 166 rural districts of nine Governorates (Adh Dhale'a, Al Hodeihah, Al Jawf, Hadramoot, Hajjah, Ibb, Lahj, Ma'rib, Taiz) using the Global Trachoma Mapping Project systems and methodologies. Fieldwork was undertaken from September 2013 to March 2015. Risk factors for TF in children aged 1-9 years were evaluated using multilevel random effects logistic regression. Results: The TF prevalence in children aged 1-9 years was ≥10% in two EUs (7 districts) and 5-9.9% in six EUs (24 districts). In adults aged ≥15 years, trichiasis prevalence was ≥0.2% in five EUs (19 districts). Being older (within the 1-9-year age bracket), being male, living in a household with higher numbers of children, and living in a household that reported the use of open defecation, were each independently associated with higher odds of TF. Conclusions: These surveys provided baseline data to enable planning for trachoma elimination. The World Health Organization Alliance for the Global Elimination of Trachoma by 2020 stands ready to assist Yemen once security considerations permit further surveys and implementation of control activities.

Section: Discussionmentioning

confidence: 89%

Prevalence of trachoma in Yemen: results of population-based prevalence surveys of 42 evaluation units in nine governorates

Thabit

Al-Khatib

Hail

et al. 2018

“…Completion of the survey was a credit to the field teams, who negotiated the terrain without complaint and returned data of high quality. 28,37 There was, however, one particular shortcoming in our survey. Because of access issues and the spatial distribution of households, as noted in the Methods section above, it was not possible to include 30 households in each village.…”

Section: Discussionmentioning

confidence: 96%

A Population-Based Trachoma Prevalence Survey Covering Seven Districts of Sangha and Likouala Departments, Republic of the Congo

Missamou

Marlhand

Dzabatou-Babeaux

et al. 2018

Purpose : We set out to estimate the prevalence of trachoma and access to water and sanitation in seven suspected-trachoma-endemic districts of northern Congo, surveyed as a single evaluation unit. Methods : From a complete list of rural villages in the seven districts, we systematically selected 22 with probability proportional to village size. In selected villages, we included all households where there were fewer than 25 in total, or used compact segment sampling to select a group of approximately 20 households by random draw. In each selected household, all consenting residents aged ≥1 year were examined by Global Trachoma Mapping Project-certified trachoma graders, and data collected on household-level access to water and sanitation. Results : In November and December 2015, 466 households were visited in 22 villages, and 2081 (88%) of 2377 residents of those households were examined. No examined individual had trichiasis. The age-adjusted prevalence of the active trachoma sign trachomatous inflammation—follicular (TF) in 1–9-year-olds was 2.5% (95%CI 0.9–4.5%). Only 39% (95%CI 35–44%) of households had access to an improved source of drinking water. Only 10% (95%CI 7–13%) of households had access to an improved sanitation facility. Conclusion : Trachoma is not a public health problem in this part of Congo. Access to water and sanitation is inadequate.

“…We assume, based on then-current practice that the presence of TS was not required for "trachomatous trichiasis" to be diagnosed at baseline, even though the survey reports refer to prevalence estimates of components. Though our survey methodology is considered best-in-class, 53 we acknowledge residual weaknesses, including the use of random walk to select households in Nigeria; reliance on self-report of access to water and use of sanitation; exclusive focus in questions about sanitation use on where household adults defecate (ignoring sites of disposal of children's faeces); suboptimal recruitment (Table 2); and relatively low sample sizes of adults.…”

Section: Discussionmentioning

confidence: 99%

Impact Survey Results after SAFE Strategy Implementation in 15 Local Government Areas of Kebbi, Sokoto and Zamfara States, Nigeria

Mpyet

Muhammad

Adamu

et al. 2018

Purpose: To determine prevalence of trachoma after interventions in 15 local government areas (LGAs) of Kebbi, Sokoto and Zamfara States, Nigeria. Methods: A population-based impact survey was conducted in each LGA using Global Trachoma Mapping Project (GTMP) protocols. In each LGA, 25 villages were selected, except in Arewa LGA, where we selected 25 villages from each of four subunits to obtain finer-resolution prevalence information. Villages were selected with probability proportional to size. In each village, 25 households were enrolled and all consenting residents aged ≥1 year were examined by GTMP-certified graders for trachomatous inflammation-follicular (TF) and trachomatous trichiasis (TT). Information on sources of household water and types of sanitation facilities used was collected through questioning and direct observation. Results: The number of households enrolled per LGA ranged from 623 (Kware and Tangaza) to 2488 (Arewa). There have been marked reductions in the prevalence of TF and TT since baseline surveys were conducted in all 15 LGAs. Eight of the 15 LGAs have attained TF prevalences <5% in children, while 10 LGAs have attained TT prevalences <0.2% in persons aged ≥15 years. Between 49% and 96% of households had access to water for hygiene purposes within 1 km of the household, while only 10-59% had access to improved sanitation facilities. Conclusion: Progress towards elimination of trachoma has been made in these 15 LGAs. Collaboration with water and sanitation agencies and community-based trichiasis surgery are still needed in order to eliminate trachoma by the year 2020.